This invention relates to glow discharge devices, especially cathode-anode gas discharge devices operated by direct current and which are capable of producing a visual display or representation of data such as numerals, letters, radar displays, aircraft displays, binary words, educational displays, etc.
Gas discharge display devices of the type contemplated herein are well known in the prior art. Examples of such devices are disclosed in U.S. Pat. Nos. 2,142,106; 3,237,040; 3,497,751; 3,260,880; 3,720,452; and 3,725,713, all of which are incorporated herein by reference.
Such devices comprise an anode and a cathode, typically in direct contact with an ionizable gas mixture. Electrical energy such as a direct current is applied to the electrodes so as to effect a glow discharge in the ionizable gas mixture between the anode and the cathode.
In the construction of the device, a continuous volume of ionizable gas is confined between opposing cross conductor arrays typically forming matrix elements. The cross conductor arrays may be orthogonally related (but any other configuration of conductor arrays may be used) to define a plurality of opposed pairs of glow discharge sites. Thus, for a conductors matrix having H rows of cathodes and C columns of anodes, the number of glow discharge sites will be H times C.
In addition to the matrix configuration, the cathode-anode conductor arrays may be shaped otherwise. Accordingly, while one conductor arrangement is of the crossed grid type as discussed herein, it is likewise apparent that where a maximal variety of two dimensional display patterns is not necessary, as where specific standardized visual shapes (e.g., numerals, letters, words, etc.) are to be formed and image resolution is not critical, the anodes and cathodes may be shaped accordingly, i.e. a so-called segmented display.
Typically, both the anode and cathode are immersed in or otherwise in direct contact with the ionizable gas mixture. However, it is also feasible to have a gas discharge device wherein some of the conductive or electrode members are in direct contact with the gaseous medium and the remaining electrode members are appropriately insulated from such gas by a dielectric or other means.